1. Field of the Invention
The present invention relates to a magnetic head, and more particularly, to a method for manufacturing a magnetic head of a MIG type in which a magnetic material of a high saturation magnetic flux density and a high magnetic permeability is provided in the magnetic gap.
2. Description of the Related Arts
In recent years, improvements in video, acoustic, and information equipment have been remarkably progressing. Magnetic recording plays a very important role in these equipments. Accordingly, there are growing demands for the development of magnetic recording technology. For example, the development of technology for carrying out a high density recording is strongly demanded. As a result, the recording medium of these equipments have increased in magnetic coercive force. A conventional magnetic head made of ferrite is not enough to record a signal favorably on a medium having such a high magnetic coercive force. Therefore, researches have been made on a metallic soft magnetic materials of a high saturation magnetic flux density such as Sendust, Co-base amorphous, and Fe-base alloy. Further, magnetic heads of various types, such as laminated types or thin film types, which are made of these metallic soft magnetic material, have been energetically developed.
A magnetic head of a metal-in-gap (MIG) type is superb in that it is low in manufacturing cost and preferably has wear resistance. The above-described MIG head means that a magnetic head made of ferrite in which a metallic magnetic material of a high saturation magnetic flux density and a high magnetic permeability is provided in the magnetic gap. Of MIG heads, a MIG head of a parallel gap type particularly has a favorable productivity, namely, a magnetic head in which the magnetic gap is parallel with the boundary surface between the ferrite and the metallic magnetic film of a high saturation magnetic flux density and a high magnetic permeability. But the parallel gap type MIG head is inferior in practicability in that a pseudo signal is produced due to the generation of a pseudo gap in the boundary region between the ferrite and the metallic magnetic film caused by reaction or diffusion in heat treatment. But recently, researches have been made to manufacture a metallic film which is hardly diffused and hardly reacts with the ferrite or the nonmagnetic reaction preventing film. The parallel gap type MIG heads comprising such films are practically used, which is described in, for example, "Japanese applied magnetics society magazine", 12, 103-106 (1988) or 13, 277-280 (1989).
The conventional parallel gap type MIG head has a disadvantage in its structure in the metallic magnetic film of a high saturation magnetic flux density and a high magnetic permeability in practical use does not have the necessary reactivity or only exhibits the property of diffusion in a slight degree. Accordingly, it is necessary to provide a parallel gap type MIG head comprising such a metallic magnetic film with a composition suitable for the metallic magnetic film. Otherwise, it is necessary to form a reaction preventing layer between the metallic magnetic film and the ferrite. If the reaction preventing layer is nonmagnetic, the reaction preventing layer itself serves as a magnetic gap. Consequently, the reaction preventing layer causes a pseudo gap.